Grate bar for sintering machines and the like



April 28, 1925. 7 1,535,695

H. L. SPENCE GRATE BAR FOR SIN'IERING MACHINES AND THE LIKE Filed Nov. 17. 1922 2 Sheets-Sheet l Aprii 2%, 1925.

H. L. SPENCE GRATE BAR FOR SIN'IERING MACHINES AND THE LIKE 2 Sheets-Sheet 2 Filed Nov. 17, 1922 talented Apr. 28, 1925.

The

isiunnnr a. SPENCE, or CLEVELAND, omo, assmnon. BY mnsnn assmnmmi'rs, 'ro narronat MALLEABLE arm s'rnnr. cas'rmos COMPANY, or onnvnnan'n, onto,

@Q'EEEIPQEIATION OF OHIO.

Application filed November 17, 1922. Serial No. 601,515.

To aZZ whom it may concern:

Be it known that l, HUBERT L. Srnnon, a citizen of the United States, residing at Cleveland, Cuyahoga County, Ohio, have invented new and useful Improvements in Grate Bars for Sintering Machines and the like, of which the following is a specification, reference being had to the accompanying drawings, in which Fig. 1 is an elevation ofa sintering machine embodying my invention; Fig. 2 is a plan of one of the pallets showing in 1mproved grate bar in outline thereon; 1g. 3 is a section through one of the pallets or cars showing my improved grate bar in elevation thereon; Fig. 4 is a plan of my 11nproved grate bar; and Fig. 5 is a section on lines 55 of Fig. 4.

My invention relates to grate bars for sintering machines and the like, and comprises a grate bar designed to resist the warping efi'ects of the sintering operation and the impact of dumping the pallets or carriers while the grate bars are in heated condition. To this end the metal in my improved grate bars is distributed in such a way as to carry the stresses in straight lines from the points of: application of the forces acting upon the grate bar to the points of support, and at the same time provides suitable apertures through which the gases have to pass. My invention also comprises the various features which I shall hereinafter describe and claim.

Referring to the drawings, I have shown my invention applied to a sintering machine of a suitable type, but it obviously may be applied to any machine in which sintering or like operations are carried on. The machine consists of a framework 2 around which is built a track-way comprised of two sections 3 and 3*. A train of small cars or pallets 4 runs on the track 3 and is moved slowly in the direction of the arrow by means of the large drive wheel 5. As the cars pass under the chute 6 at the loading point A they are loaded with the material to be sintered and pass slowly toward the left. After passing the loading stagze A they move beneath an igniting torch at the point B. Located beneath this portion of 'the track 3 is a series of suction fans 8 which draw the burning gas down through the material on the pallets 4;, raising it to a sulficiently high temperature to cause it to sinter or agglomerate into a more or liess solid mass. The combustion "continues as the cars move toward the left-hand end of the machine, and at the point C the sintering or agglomerating process is supposed to be complete. When the cars reach the lefthand end of the machine the tops of the Wheels 4 are engaged by a separate section 3 of the track-way, so that as the pallets 4 fall over the dumping end of the machine they are prevented from derailment by the track 3, and drop down a short distance to the dumping position D and strike the rear end of the preceding pallet 4. This dro ping is for the purpose of breaking up t e material and dumping it.

After dumping, the empt pallets 4 then travel on the section 3 o the track-way around the under side of the machine and the wheels 4* again become en aged by the section 3 of the track, upon w ich they are moved along to the loading platform A. In the type of machine illustrated the cars 4: are not coupled together, but simply ush one another around under the im ulse o the driving wheel, so that each car is cc to drop by gravity when it reaches the dumping end of the machine.

Due to the heating of the grate bars from the material and the impact of the dum ing operation the grate bars are subjected to severe warping strains and also to distorpallet ribs 10. Each grate bar 9 preferably abuts against the next bar on the pallet through the small spacing lugs 11' and is held on the pallet during the time they are inverted by the pins 12, which fit into notches 13 in the tops of the bars. As each pallet dro s over the dumping end of the machine, t e pins 12 are the points of support, and the inertia eifect of the bar and the load, when the pallet is suddenly brought to rest by striking against the preceding pallet, sets up bending stresses in the bar, tending to bend the'bar in the direction of travel, as indicated by the arrows E and 1 the broken lines in Fig. '2. For the purpose of resisting this tendency to distortion my improved grate bar has the air holes or slots 14 near each end so arranged as to leave continuous strips 15 of metal running from each end of the bar diagonally toward its side edges 16 and toward the center of each such side 16, which results in an arrangement which may be compared to 'a diamond truss, allowing the stresses of tension and compression to be carried by these strips 15 of metal directly from the points of support at the pins 12 to the sides of the bar in such manner that these stresses are distributed along the sides of the bar without concentrating any heavy load at one point in the sides of the bar. As the bendin stress will be greatest half-way between t e ends of the bar and will be comparativel slight near its ends, the sides 16 of the ar are made thicker near their centers and are tapered off toward each end. As a further reinforcement the sides 16 of the bar may be made higher at the center and tapered down toward each end. 'By this arran ement the cross-sectional area of the side e ges of the bar is made approximatel proportional at each point to the stresses t ey must carry at each such point. Inasmuch as the weight of the material carried by the bar sets up transverse bending stresses which are greatest near the center of the bar, the slots 17 are there run transverselythat is, approximatel at right angles to the axis of the bareaving continuous strips 18 of metal running from one side of the bar to the other to strengthen the bar near its center against stresses set up by the weight of the material. As is shown in Fig. 5, the slots 14 and 17 are tapered so that the strips 15 and 18 give a broad supporting surface for the material and are cut away on their under sides so as to minimize weight and prevent clogging of the slots.

As somewhat similar, although lesser, stresses are imposed upon the bar all the way out to its ends the diagonal slots 14 are preferably so arranged that: there are continuous strips 19 of metal between the ends of such slots running from side to side of the bar.

I have found that grate bars constructed in accordance with my invention are suitable for resisting distortion when used in the manner which I have described, since the distribution of metal is effected in such a manner as to place the metal straight in tension or compression and to carry the stresses in straight lines from the point of application to the point of support. By making the sides of the bar thicker near the center andta ering them toward the end I have provide for a reinforcement against the greater stresses carried by the center of the bar.

I have found that my improved type of nbsaeet grate bar is much more rigid and durable than other types under the impact of the dumping operations, and at the same time there is little or no increase in weight over existing types of bars, nor any reduction in the slot area provided Ior the passage of gas therethrough.

The terms and expressions which I have employed are used as terms of description and not of limitation, and I have no intention, in the use of such terms and expressions, of excluding any mechanical equiva lents of the features shown and. described, or portions thereof, but recognize that various structural modifications are ossible within the scope of the invention claimed.

What I clalm is:

1. In grate bars for sintering machines and the like, a traveling support upon which the grate bar is mounted, means for holding the grate bar.in position on the support during dumping operations, said grate bar having strips' of metal running from the ints of support toward the central portlon of the sides of the bar so as to permit the transmission of stresses direct from the point of application to the point of support, and apertures between said strips for the passage of gases through the grate bar.

2. A grate bar for sintering machines and the like having means for supporting its ends, continuous strips of metal running from the points of support toward the center of one of the sides, and. other continuous strips of metal near the center of said bar joining the sides thereof, the said bar having series of apertures between said strips.

3. A grate bar for sin'tering machines and the like having means for supporting its ends, continuous strips of metal running from the region about the points of sup- 1 port toward the center of one of the sides,

and other continuous strips of metal near the center of said bar extending transversely of the bar and joining the sides thereof, the said bar having series of apertures between said strips, each side of the bar being uninterrupted from end to end and having a greater cross sectional area near its center than near itsends.

4. In a grate bar for sintering machines and the like having means for supporting its ends, continuous strips of metal running from the points of support toward the center of one of the sides, and other continuous strips of metal near the center of said bar joining the sides thereof, the said bar having series of apertures between said strips some of which are arranged diagonally and some of which are arranged transversely of the bar.

5. In a grate bar for sintering'machines and the like having means for supporting its ends, continuous strips of metal running from the points of support toward the center of one of the sides, and other continuous strips of metal extending transversely of the bar and joining the sides thereof, the said bar having series of apertures between said strips, some of which are arranged diagonally and some of which are arranged transversely of the bar.

6. A grate bar for sintering machines and the like having means for supporting its ends, each of the two sides of the bar being continuous from end to endv and being of greater cross sectional area at its center and of lessening cross sectional area toward its ends, the web of said bar being apertured for the passage of air or-gas s therethrough and having continuous strig of metal extending from each end of t e bar in the direction of the center of one i of its sides.

HUBERT L. SPENOE. 

